Engine starter



Oct.l 14, 1930. R. ABELL 1,778,011

ENGINE S TARTER Filed Sept. 30, 1924 f H2* 1 1? Q//g/i i p11' 26 Patented Yct. 14, 1930 i PATENT OFFICE i ROLLIN ABIELL, OF MILTON, MASSACHUSETTS ENGINE STARTER Application filed September 30, 1924. Serial No. 740,728.

This invention relates to starters for internal combustion engines, and especially to starters of the type in which .a starting pinion is shifted into gear and rotated by an axially movable and rotatory transmission device.

One object of the invention is to provide 'improved means for softening the a/pplication of the operating torque to the starting 39 pinion, and another is to provide for softening the axial movement by which the pinion is shifted into gear, so that neither the pinion nor its shifting mechanism will be subjected to a violent shock or impact either when starting it toward or arresting it at its operative position. v

A feature of the invention consists in a rotary and axially movable transmission unit arranged to shift a starting pinion axially to an operating position, this unit also serving to drive the pinion and including. for this purpose, a pair of cooperative camming mem- "bers one of which has a camming surface of lgraduated pitch the steepest portion of which is within the angle of repose. The effect of this camming couple is to develop the operating torque gradually so that no sudden shock or impact will occur at the instant of initiating rotation of the starting pinion whether the load be'light-or heavy. This camming couple is preferably supplemented by a spring arranged to resist the cammmg action and thereby spread the development of the operating torque over a greater range of cammmg motion than if spring resistance were omitted.

l Another feature of the invention consists in improved means for shifting the starting pinion axially into gear with agradually d1- minishing speed in the latter stages of move.- 4

-9 ment.` As shown, this feature is provided by a rotatorv cam member having duplicate cam surfaces bf graduated pitch for producing the axial shifting movement of the starting pinion, said cam surfaces, unlike those in prior constructions, being curved to decelerate the speed in the latter stages of shifting movement. y. u

As shown, the aforesaid cam member is provided with high spots formed and ar- O ranged to perform another novel function, viz,

/to maintain the starting pinion in its operative position in case of momentary relief of the starting torque caused by an incompleted starting of theyengine.

Although the duplication of the aforesaid cam surfaces and high spots is preferable for the sake of balance and ease of operation, the principles of the invention are not limited to this duplicate construction.

Still another novel feature, but one which relates to the cam surfaces above mentioned, consists in a curve for developing a gradually accelerative axial movement during the early stages in combination with the aforesaid curve for decelerating such movement during the latter stages. This double effect, which I consider broadly new, is conveniently obtained by cam surfaces of ogee curvature, and may be developed to an extent that will produce acceleration from zero degree to a maximum degree and deceleration from said maximum degree to the zero degree. Thus, the action of the operating member is soft and gentle in the initial stages to start the axial movement of the pinion as well as in the latter stages to arrest such movement, and it is to be observed that these desirable effects are produced without a spring. So far as I am aware no prior construction has had an operating member that functions with a decelerating effect. as the pinion approaches its working position.

An advantage of incorporating the firstmentioned camming couple into the axially movable transmission unit is that its effect is segregated from that of the camming couple that produces the axial shifting movement. Consequently, the reaction of the camming surface of the first-mentioned couple cannot disengage the pinion from the driven gear of the engine, that result being exclusively under the control of the camming couple that shifts the pinion to its operative position. In consequence of thus segregating the two caniming couples it is possible to form the camming surfaces of the twocouples according to the requirements of each of them without any limitation due to the other.

Preferably, and as herein shown, the two camming couples are so designed and related ed by the drawings.

Referring tothe drawings; Figure 1 is a side elevtion of a starting gmechanisml embodying the invention in a lform which I consider preferable, and includes broken lines representing portions of a, starting motor and a gear of an internal combustion engine.

FigureA 2 is a longitudinal section of the startmg mechanism.

rc3 is a development of the operating mem er of the mechanism.

Figure 4 is an elevation of the clutch memblalrs that develop the operating torque graduy. Figure 5 is an end elevation of the members shown in Figure 4.

.Figure 6 is an elevation of a disconnectible- "releasing clutch by which rotation istransmitted tothe stationary pinion.

Referring to Figure 1, a portion of the casing of an electric .starting motor is represent- -ed at 10, and the armature shaft at 11. A

- spur gear 12, shown by broken lines, `represents the gear-usually formed on or fastened to the flywheel of an engine. The motor shaft 11 projectsl a few inches from the casing 10 to carry the starting mechanism and-is held against axial movement by any suitable means, not shown.

.1- vThe Ioperating member of the starting l. Y mechanism is indicated at 14 and is fastened 1.45,.

to the Vshaft 11 by a set-screw 15. This` member is a cylindric shell and is formed with duplicate cambslots 16 diametrically opposite to each otherto receive lugs or stud portions 17 formed on --a *collar 18. The surfaces that ,formthe slots 16 lhave o ee curvature, both end portions of each slot eing substantially tangential to planes at right angles to theaxis f of rotation.

- each other by 'a distance necessary to shift the startingpinion into and out of gear, and the hese planes are offset from slots are formed to`develop the axial movement with an' accelerative effect from'the zero degreeto the maximum degree during the first half of the total range of axial movement and to effect deceleration from the maximum degree'to the' zero degree during the second' half. The slots are open at 19 to permit assembling the parts, and the surfaces 2O extending parallel to the axisof rotation to provide driving abutments by which the opand are illustratf erating torque is applied to start the engine.

It is to be noted that the lug 17, after reaching the high spot of the'cam as shown in Figure 3, is still a considerable distance from the driving abutment 20, and that the surface 16X on which it runs thereafter has no appreciable rise .or camming action. This idle surface 16X functions, as hereinafter explained, to prevent demeshing ofthe pinion in case of a momentary relief ofthe starting torque caused by an incomplete starting of the engine.

The collar 18 surrounds a sleeve 21, Athese two members forming a novel type of resilient clutch, being'telescopically related and having relativeaxial movement and relative rotary movementbotl1 slight, to provide for a gradual development of the starting torque.

The driving connection between them is provided bydiametrically opposite lugs or stud portions 22 formed on the sleeve, and semicircular concave cam surfaces provided by notches 23 formed in the collar `to receive them. l

The sleeve 21 is arranged to slide axially on the motor shaft 11 and the two are capable of relative turning movement. A starting pinion 24 surrounds the sleeve 21 and these two also are capable of relative axial movement and turning movement. An outer sleeve 25 screwed onthe sleeve -21` connes the pinion and is elongated to bear in the motor casing which, as shown, provides a journal for it.

A compression spring'26, under initial compression between the pinion and the collar 18, keeps the 'latter against the studs 22 `and keeps the pinion against the sleeve 25. The

abutting ends of the pinion and sleeve are formed with cooperative clutch teeth 27 by which rotation is transmitted from the sleeve to the pinion to start the engine. The driving surfaces of these'teeth are inclined to theA axis of rotation to prevent the development of torque above a degree that can safely be imposed upon the mechanism. lf the engine backres or fails to respond when the starting mechanism is operating, the driving connection between thel pinion and the clutch- ,sleeve is automatically ruptured by the reaction of the inclined driving surfaces and the teeth of the sleeve click over those of the pinion witho'ut unduly straining the mecha- Referring to Figures 2 and 4, the driving connection between the collar 18 and the Sleeve 21 is designed to develop the startingV torque gradually sothat the action of the mechanism on the engine gear 12 will be soft without sacrificing power. When the collar 18 starts to turn, the load on the sleeve 21 causes the collar to gain relatively to the sleeve. Then the reaction of the studs 22 on the curved surfaces tha-tuform the notches 23 develops the torque gradually `and with a rapidly increasingratio, assisted by the com- CTI pression spring 26 which resists the relative axial movement caused by the relative turning movement. As the steeper portions of the curved ,surfaces come into contact with the studs 22 the torque is developed to a degree so nearly posit-ive that it turns the clutch sleeve 25 in any event. If the engine gear 12 responds the pinion 24 and sleeve 25 will remain in clutched relation and turn as one, but if the load on the engine gear is abnormally great the inclined driving faces of the clutch teeth 27 will, by their reaction, repel the pinion against the force of the spring 26 and permit the sleeve 25 to rotate while the pinion remains locked with the engine gear.

The illustrated construct-ion is such that 'the collar 18, sleeve 21 and sleeve 25 constitute an axially movable and rotatable transmission unit by which the starting pinion is shifted axially and rotated. Furthermore, the conjoint actions of the collar 18, sleeve 21 and spring 26 provide a softening eifect on the starting action, while the softening effect upon the axial shifting is afforded by the novel form of the cam surfaces in the operating member 14.

A spring 30 is preferably arranged to oppose axial movement of the trasmission unit to its operative-position. V"For this purpose the starting shaft 11 is formed with a shoulder 31 to provide an abutment .for the spring, and the sleeve 25 is formed with an internal abutment 32. The spring is initially relaxed and the space between the abutments 81, 32 is greater than the normal length of the spring by a distance greater than that necessary to shift the pinion into meshed relation with theA gear 12. '1

In operation* the pinion goes in gear before the` sleeve 25 begins to compress the spring 30, but during the latter stages of axial movement of the transmission Vunit the said spring will undergo compression and such axial movement on the part of the transmission unit will cease when the abutments 20 and lugs 17 are in or near the relation shown in Figure 3. Here, it is to be assumed that the operating member 14 is moving 1n the direction indicated by an arrow.

When the spring 30 is compressed by shifting the transmission unit to its operative position it takes up loose play in the parts and reduces the noise caused bv the impact of the driving abutments 20 against the lugs 17. Moreover, the pressure of the lugs 17 against the non-inclined surfaces 16x, due to the deiiection of the spring 30, develops a considerable factor of friction which resists the return of the lugs 17 to the inclined cam surfaces. This latter eifect is not su'licient to prevent the lugs from returning to their initial positions in thecam slots wheneve-r a successful starting of the engine is accomplished, but it is suicieint t'o prevent demeshing of the pinion 24 in case of an incompleted starting of the engine, as, for example, when an explosive impulse iny but one cylinder of the engine produces a rotary impulse but is not followed immediately by impulses in the other cylinders. Thus, the non-reactive arrangement of the surfaces 16x, supplemented by their frictional resistance above referred to, keeps the pinion in mesh until regular operation of the engine is effected.

lVhen the starting mechanism is not operating, the parts occupy the positions shown in Figures 1 and 2. f By energizing the starting motor, represented by the element 10, the shaft 11 is caused to turn in the direction indicated by arrows in Figure 1. The inertia of the transmission unit holds the xlatter against rotation while the cams 16 shift the pinion into gear. Rotation of the collar 18 will begin when the abutments 20 strike the lugs 17, whereupon the curved surfaces 23 of said collar will function to develop the operating unit. Consequently, the lugs 17 I will move aheadk in the cam slots 16 with the result of shifting the pinion out of gear and back to its initial position as shown in Figures 1 and 2.

What I claim is: n

1. An engine-starter comprising a starting pinion, and a rotary and axially movable unit arranged to shift said pinion axially and impart rotation thereto, said unit comprising two relatively movable clutch members and a spring arranged to maintain them normally in one relation, one of said clutch members having a lug and the other having a semi-circular concave cam face for cooperating with said lug to develop the operating torque gradually from a loiv degree to a high degree.

2. An engine-starter comprising a starting pinion, a' rotary but axially stationary operating member, and a. rotary and axially movable unit arranged to shift said pinion axially and transmit rotation thereto from said operating member, the operating con` nection between said operating member and said unit including a cam face of gradually diminishing pitch to shift said unit axially with a decelerating speed. 3. An engine-starter comprising a start. ing pinion, a rotary but axially stationary operating member, and a rotary and axially movable unit arranged to shift said pinion axially and transmit rotation thereto from said operating member, the operating connection between said operatingfmember and4 ating member, and a rotary and axially mov-` able unit arranged to shift said pinion axially and transmit rotation thereto from said' operating member, the operating connection between said operating member and saidmnit including a cam face, one portion of which is curved'to develop axial movement with accelerating sneed and the other of which isotherwise curved to decelerate the axial movement. y

5. An engine-starter comprising a starting pinion, a rotary but axially/stationary operating member, anda rotary and axially movable unit arranged to shift said pinion axially and transmit rotation thereto from said operating member. the operating connection between said operating member and said unit including a cam face having successive portlons one of which 1s curved to. develop axialvmovement accelerating to a maximum degree and the other of which is otherwise curved to diminish the axial movement gradually from said maximum degree to zero deee. 4 gr6. An engine-starter comprising a starting pinion, a rotary but axially stationary operating member, and a rotary and axially movable unit arranged to shift said pinion axially and transmit rotation thereto from said `operating member, said operating member being hollow and having a cam surface to impart the axial movement to said unit,

and said unit including relatively movable members nested in said operating member and organized -to develop the operating torque gradually. p l

7. An engine-starter comprising a starting pinion, a` rotary, but axially stationary operating member, anda rotary and axially movable unit arranged to shift said pinion axially and transmit rotation thereto from said operating member, said operating member being hollow and having a cam surface to impart the axial movement to said u nit, and said unit including a collar nested in said operating member afnd a supporting member on which said collar is arranged to turn and slide, said collar having a lug or follower to cooperate with said cam surface and having a curved driving surface, and

said supporting member having a lug arranged to cooperate with said curved driving surface to develop the operating torque gradually. l

8. An engine-starter comprising a rotary but axially stationary operating member consisting of a. hollow barrel cam, a rotary and axially movable unit, .and a, starting pinion carried by said unit, said unit including two telescopically related members nested in said operating unit, a rotary and axially movable transmission unit provided with a starting pinion, and a spring arranged to'oppose axial movement of said transmission unit to its operative position, one of said units having a driving lug and the other having a driving abutment'and a cam surface leading thereto for cooperating with said lug, said cam surface terminating adjacent to said driving abutment in a portion arranged to maintain said transmission `unit in its operative position in case of momentary relief of the starting torque caused by an incompleted starting of the engine.

operating unit, a rotary and axially movable transmission `unit provided with a starting pinion, and a spring arranged to oppose axial movement of saidtransmission unit to its operative position, one of said units having a driving lug and the other having a driving abutment and a cam surface leading thereto for cooperating with said lug, said cam surface terminating adjacent to .said driving abutment in a portion at right angles to the axis of rotation whereby said transmission unit is maintained in operativeV position in case. -of momentary relief of the starting torque caused by an incompleted` starting of the engine. 1 11. In an engine starter, a rotary and axir 10. An engine starter comprising a rotary ally movable transmission sleeve provided thereby balance the torque and the load, and 1 means arranged to shift said collar axially and drive it.

12. In an engine starter, a rotary and axiallyv movable transmission sleeve provided with a driving lug and an abutment spaced apart axially, a driving collar and a pinion arranged on said sleeve Ibetween said lug and I said abutment, and a compression spring between and abutting said collar and said'pin-i ion,said abutment and said pinion having Aceoperative clutching surfaces forming an overrunning clutch, and said collar having aconcove camming surface engaging said lug t0y ycompress said sprlng and thereby balance the torquel and the load and also develop clutching pressure of said pinion against said abutment. i

13. In an engine starter, a rotary and axially movable transmission sleeve provided with two abutments lspaced apart axially, a driving collar and a pinion arranged on said sleeve between said abutments, and a com pression spring between and abutting said collar and said pinion, one of said abutments and said pinion having cooperative clutching surfaces forming an overrunning clutch, and the other one of said abutments and said collar forming Va lost-motion driving connection including a concave camming surface by which said spring is compressed to balance the torque andthe load and to develop clutching pressure of said pinion against the abutment first specified.

14. An engine starter comprising a' rotary operating member, a rotary and axially mova le transmission unit provided with a starting pinion, and a spring arranged to oppose axial movement of said unit in one portion of said cam surface being non-reactive and arranged to maintain said unit in an axially advanced ositlon, said connect1on also lncludlng r1v1ng abutments ar- .ranged to be brought into cooperative engagement with eachother when said 'terminal portion of the cam surface functions as aforesaid.

15. An engine-starter comprising an axially movable transmission unit including a starting pinion, aprotar operating member having a camming sur ace arranged to act on said transmission unit to shift the latter axially to an operative position, and a; spring arranged to oppose axlal movement of said transmission unit to said operative position,

-said operating member also'having a noncamming surface forming a continuation of said camming surface to maintain the unit positively against reflex action of said spring, and said operating member having a driving abutment arranged to rotate said unit whenY said non-camming surface is acting as aforesaid. a

16. An engine-starter comprising an axially movable transmission unit including a starting pinion, and a rotary operating member having a camming surface arranged to act on said transmission unit to shift the latter axially toan operative position, said operating member also having a non-camming surfaceforming a continuation of said camming surface to maintain the transmission unit positively in said operating position until the engine starts, rsaid operating member having a driving abutment to rotatev said unit when said non-camming sur- In testimony whereof I have aiixed my i signature this tenth day of September, 1924.

ROLLIN ABELL. 

